(i) The First World War was fought from 1914 to 1918.• It led to huge increase in defence expenditure which was financed by taxes.• Due to war prices increased many times leading to extreme hardship for common people.• Crops failed in 1918-19 resulting in acute shortage of food.• Many people lost their lives in the war and due to epidemic.• Forced recruitment in the army caused widespread anger.(ii) Gandhiji’s Return and Satyagraha : Mahatma Gandhi returned to India from South Africa in 1915 where he had successfully fought against the racist regime with his new method of mass agitation and nonviolence known as Satyagraha. In India he launched satyagraha movements at various places. These satyagrahas provided base to the Non-Cooperation Movement.(iii) The Rowlatt Act : The Act was passed by the Imperial Legislative Assembly. The act provided enormous powers to police. The police got the power to arrest anyone without any trial. The aim of the act was to repress political activities.